1. Field of the Invention
This invention relates generally to the processing of meats and more particularly to the processing of meats using a vacuum to chill the meat.
2. Description of the Prior Art
It is known to process meat, especially ham, by injecting a cure solution into the meat and then placing the meat into a tumbler and processing it while under a vacuum. Because the tumbling action creates heat and it is preferred to keep the meat cool, refrigeration is also added to the tumblers. Such a process for treating meat is disclosed in U.S. Pat. No. 4,409,704. The vacuum being used in the process described in U.S. Pat. No. 4,409,704 is utilized to assist in increasing the rate of myosin release, and is not used to cool the process. Separate refrigeration coils are utilized for that purpose. The external refrigeration sources for such tumblers have usually been either a cryogenic gas such as CO.sub.2 or combinations of mechanical refrigeration equipment and a cryogenic gas. These systems have a high initial cost as well as ongoing high overhead costs. In the case of CO.sub.2, other problems are incurred such as rapid wear of vacuum components due to formation of corrosive carbonic acid, reduced vacuum during CO.sub.2 injection, freezing up of vacuum ports, and a potentially hazardous working environment.
In addition, there are vacuum cooling apparatuses which are used to cool meat by evaporating the water on and in the meat. Such an apparatus is disclosed in U.S. Pat. No. 3,423,950. The apparatus disclosed in U.S. Pat. No. 3,423,950, does not tumble or process the meat as does that in the process disclosed in U.S. Pat. No. 4,409,704. The vacuum used in U.S. Pat. No. 3,423,950 is at a pressure of 4.6 mm. absolute.
While vacuum cooling has been utilized in meat processing, it has not been utilized to date in a tumbler for processing meat. The present invention provides for a tumbler which utilizes the vacuum for cooling as well as to assist in increasing the rate of myosin release. There is no separate source of cooling, other than the vacuum.